It's funny in hindsight. The client has asked a very speculation-heavy question, without giving you enough context to answer it. You open your mouth to ask a question, but your sales rep beats you to it. He isn't asking a question though. He's explaining functionality in a way you've never heard it explained.
In a way, it was never designed. You attempt to interrupt, but the client looks delighted, and your sales rep, encouraged, continues to add dots and dashes and details to the fictional tool he's now describing.
Hey, I said it was funny in hindsight. At that moment, however? Horrifying. It's almost primal - you're caught in a lie, your hand in the cookie jar, and the next words out of your mouth better be magic.
One of the skills we SEs never list on our resumes and yet almost always possess is the ability to 'un-explain' fictitious functionality. However much we un-explain later though, the damage usually remains.
Sometimes, if the gaff is big enough, the client loses faith in our word as a company. Other times, they fixate on the *one* thing the rep miscommunicated, and use that as a bargaining chip. Still other times, they remember they were promised 'something different.
The fact is that misinformation is very, very common in sales, and often, completely unintentional. But since nearly every client has had at least one bad sales experience, and the less we remind them of those, the better.
What To Do When It Happens
It's happening. Your sales rep just went off script and began explaining a feature that doesn't exist.
Interruption is okay.
A timely "let me rephrase that" or "not to contradict [rep name], but technically…" will save you a world of un-explaining once the client latches on to what your rep is saying. Get in quick, and course correct. Do it with a smile.
Redirection is better.
Particularly, if the discussion is veering into contentious territory. I've been in a situation where a client wanted the *exact* functionality from a competitor's product he'd used before, even though what my company's product offered was a simpler solution and fit his process better. Since my sales rep had already said it was 'possible, I needed to do better than just contradict him. I asked the client if he was okay to "take it offline" and showed him our functionality in a one-on-one product demo later that week. Problem solved.
Correct and clarify right then.
Don't let the client walk out of the meeting misinformed. Once they've had a think about it, and begun to factor it into the solution they're building in their heads, it gets much harder to walk it back. Make the correction in the sales meeting, as quickly as possible, even if it makes you look like you're contradicting one another. You're going to have to correct it at some point anyway, and in my mind, the lesser evil is to do it then and there, apologize and recover.
Offer to come back with 'ballpark' timelines for 'wish list items.
There are times when a client gets enamoured with the fictitious solution or feature your sales rep talked about. When correction and redirection fail, instead of refusing outright, offer to come back with ballpark timelines. In the meantime, offer to build a solution with the functionality you do have, and let clients know they'll be able to upgrade to new functionality when it becomes available.
What To Do After The Discussion is Over (Client facing)
You can't control what sticks in a person's memory. Often, clients remember what they want to, even after you've made a correction. Document what was ultimately promised in the meeting, preferably the same day, by email.
Evaluate if the fiction is valuable.
Is the fictional solution a good solution? Or does it just sound good? Resist the urge to dismiss it, and check with the product team about whether it makes sense, and if not, then why not. This way, when you talk to the client later, you are able to give them context.
Meet the need, not the want.
You know this. Just because a client asks for something, it needn't be what his process or business needs. Offer to spend time with the requestor, and try getting into the details with them. Your solution will be stronger for it.
What To Do After The Discussion is Over (Internal)
Understand what went wrong, and where the misinformation came from. Often, the sales rep has just confused themselves. Sometimes they're new and feeling the pressure to close. Sometimes they come from organizations where 'stretching is considered okay. Once you know the cause, work with the rep to fix it. Use humour. Use empathy.
Institute teaching moments.
Giving feedback is easier when there is a name for it. You'll find that your sales reps are more receptive, and they don't feel singled out when it's something you do with a rep as a process.
Do so with empathy. Circulating a list of Incorrectly Answered Questions, or maintaining a shared document is easy, but tends to be ineffective. If you have regular meetings, request a 5-minute slot so you can discuss the incident, without naming or identifying the rep, and share the lesson.
Set up signals.
No matter how long you work together, or how experienced your rep is, everyone messes up from time to time. Set up signals that allow you to flag to your sales rep when they've gone off script, so they can stop, and pass the question along to you with a quick "Actually, [SE name] explains this much better."
It usually feels worse than it is.
What's important is how you recover from it. In my experience, clients understand. Most clients can tell when misinformation was intentional. If you're not in that camp, you're okay. Apologize, and come back strong. Have the intention to recover trust, and you will.
Remember, as an SE, you're in it for the long haul with these customers, and you'll have several opportunities to show them that you're championing their cause.
As with all things, it's what you do consistently that matters.